The polyphenylene oxides and methods for their preparation are known in the art and are described in numerous publications, including Hay U.S. Pat. Nos. 3,306,874 and 3,306,875. The Hay processes are based on the use of copper-amine complex catalysts. Manganese based catalysts for the oxidative coupling of phenolic monomers in the formation of polyphenylene oxides are disclosed in McNelis, U.S. Pat. No. 3,220,979; Nakashio, U.S. Pat. No. 3,573,257; Nakashio, U.S. Pat. No. 3,787,361 and Olander, U.S. Pat. No. 3,956,242. In the applicant's copending applications Ser. No. 491,475 filed July 24, 1974 and Ser. No. 534,903 filed Dec. 20, 1974, there are disclosed novel procedures for polymerizing polyphenylene oxides with complex manganese based catalysts. All of these patents and applications are hereby incorporated by reference.
In U.S. Pat. Nos. 3,444,133 and 3,455,880, there are disclosed manganese chelates of bis-salicylaldehyde ethylene diimine wh ich are reported to be useful in the preparation of polyphenylene oxides. Japanese printed patent applications 26396/73 and 26398/73 also disclose catalysts which may be manganese or cobalt complexes of one or more compounds selected from the group consisting of primary amines and aliphatic, alicyclic and aromatic aldehydes. None of these citations discloses a manganese chelate derived from a benzoin-imine or suggest its use in the oxidative coupling of phenolic monomers under basic conditions.
Accordingly, it is a primary object of this invention to provide a novel manganese catalyst for the oxidative coupling of phenolic monomers.